Control means for liquid fuel injection pumps for internal combustion engines



June 23, 1959 M EVANS 2,891,415

' CONTROL ME IS FOR LIQUID F L'INJECTION PUMPS FOR TERNAL. COMBUS NENGINES Filed May 13, 1957 2 Sheets-Sheet 1 June 23, 1959 2,891,415

F. M. EVANS CONTROL MEANS FOR LIQUID FUEL. INJECTION PUMPS FOR INTERNALCOMBUSTION ENGINES Filed May 13, 1957 2 Sheets-Sheet 2 CONTROL MEANS FORLIQUID FUEL INJECTION PUMPS FOR INTERNAL COMBUSTION ENGINES FraserMackie Evans, Acton, London, England, as'signor to C.A.V.- Limited,Acton, London, England Application M y 13, isspseria No. 658,604 1Claim. c1. 74-603) This invention relates'to liquid fuel injection pumpsfor internal combustion engine's of the kind having .one or morereciprocatory plungers', and in which the effective length of theplunger strokes is variable by a spring-loaded and endwise movablecontrol bar responsive to the action of a speed governor or otherautomatic means, or the driver.

To enable a supply of fuel in excess of the normal maximum to beobtained temporarily when starting the engine a control device operableby the driver "is required, and the object of the present invention isto enable such a device to be provided in a convenient form.

A control device in accordance with the invention comprises thecombination of a hollow body part adapted to be secured to the pumphousing around one end of the control bar, a push piece operable by thedriver, a cam pivotal-1y mounted on the push piece and serving as a stopto determine the normal maximum and the extra supply positions of thecontrol bar, and a spring acting on both the cam and the push piece, thecam having formed on it a finger like extension which in one position ofthe cam can enter a recess in the adjacent end of the control bar and alobe which can slide along a groove in the body part, or in an insert inthe body part, the device being adapted to operate as herein described.

In the accompanying drawings, Figures 1 and 2 are sectional sideelevations illustrating a control device in accordance with theinvention, Figure 1 showing the device in the condition in which itdetermines the normal maximum fuel supply, and Figure 2 showing thedevice in the condition in which it enables an extra fuel supply to beobtained when starting the engine. Figure 3 is a similar view to Figure1 illustrating a modified construction of the device. Figure 4 is adiagrammatic part sectional side view illustrating the device shown inFigures 1 and 2 applied to a fuel injection pump provided with a speedresponsive governor.

Referring to Figures 1 and 2, the control device there shown is providedwith a hollow cylindrical body part a, adapted to be secured to the pumphousing b around one end of the spring-loaded and endwise movablecontrol bar c. The said body part is adapted for screw-thread connectionwith an externally threaded end of a bush d, surrounding the controlbar, and also is provided with a thin flange e which canabut against theadjacent face of the pump housing. This flange is slit to form a tonguej, which can be pressed into a recess g, in the said face of the housingto lock the said body permanently to the pump housing. On the outer endof the body part is attached an adjustable sleeve h, in screw-threadconnection with the body part a. Within the body part is contained aslidable cylindrical push piece i, on which is formed a stem 1'extending through a central hole in the outer end of the sleeve h.Across the portion of the push piece which lies within the body part isformed a transverse slot, and in this slot a cam k is secured by a pivotm.

a shoulder u, on the push piece. ;spring can bear onlthercam. v -Afte'rthe device has..been placed 'in position .on the 2,891,415 Patented June23, 1959 positions of the cam can abut against the base of the slot inthe push piece and so hold the cam against undesired rotation. 1

.The push piece is loaded by a spring I, contained in the body part, oneend of the spring being supported by The said end of the pump, and-the.necessary,.initial adjustment has beer made to determine the normalmaximumlfuel supply position of the push piece suitable for the enginewhich the pump is required to supply, it is desirable to lock the sleeveto prevent unauthorised interference with the adjustment. This provisionmay be made in any convenient manner, but preferably it consists of anouter sleeve v. which is pressed tightly on to or is otherwisenon-remov' ably secured to the other sleeve h, and in the outer end ofthe additional sleeve is formed a polygonal or other non-circular holethrough which the stem of the push piece extends, the said stem beingmade to a section conforming with the shape of the hole.

The arrangement is such that during normal running conditions of theengine the cam occupies a position in which the axis of the finger piecen, is inclined to the axis of the control bar as shown in Figure 1. Inthis position the finger piece serves to determine the normal maximumfuel supply position of the control bar c, movement of the bar from thisposition having the effect of reducing the rate of fuel supply to theengine. This movement of the control bar may be effected by a speedgovernor as, for example, in Patent No. 2,795,219. Thus, in Figure 4such a governor is indicated by 5, and is connected by a lever 6 andlink 7 to the control bar 0 of the pump 8, the latter and the governorbeing of well known form, and the spring loading of the control barbeing effected in this embodiment by the springs 9 of the governor.Alternatively, the movement of the control bar may be efiected by otherautomatic means or by hand. When an extra supply of fuel is required forstarting the engine, the driver pushes the push piece 1', inwardlyagainst the action of the spring I. The first efiect of this is to pushthe control bar c in the same direction until the lobe p, on the camreaches the inner end of the groove q, in the body part, and theengagement of the lobe with the end of the groove causes the cam to beturned to the position in which the finger piece is opposite the recess0, in the control bar. The latter can then return (under the action ofits spring) until it abuts against the portion of the cam at the root ofthe finger piece. On release of the pressure on the outer end of thepush piece, both control bar and push piece return together until thepush piece is arrested by the outer end of the sleeve h, as shown inFigure 2. When the control bar is in this position it enables the pumpto give the desired extra fuel. On'starting the engine, and whensufiicient speed has been attained, the control bar is moved by itsactuating means to a position in which it is clear of the finger piecen. The cam is then turned by the asso-v ciated spring t, to the positionin which it restores the initial inclined position of the finger piece.If the driver actuates the push piece while the engine is running andholds it in he thereby merely reduces the fuel supply below the normalmaximum. The device therefore can effectively frustrate any :attempt by-the driver to obtain extra fuelfromthupumpexcepting When-starting theengine.

The modified construction shown in Figure 3 is essentially the same: asthe --construct,ion above described, -but ditfers in thatthe body-partwisext'ended and the part h is inserted inscr'ew thread connection withthe-interior of the body part a, the grooveiq in'whieh the lobe p of thecam can 'slide being provided in the part h. The sleeve v isnon-removably secured to thebody part by a tongue piece w, on thesleevewhich engages a groove x in the body part.

Having thus described my invention what I claim as newand desire' tosecurebykettersifat'ent' is:

Control means for a liquid fuel injectionr-pump of the kind-havingat-least oneirecipmc atory plufiger,=arid a spring-loadedandiendwisemo'vableeontrol "bar for varying the :effectivelengthmfiithexplunger' stroke; and thereby varying the pump outpug'ieomprising:in combination with the control barwhich atfonwendzis-provided with a central recess, a relatively=stationary:hollow:bodyinto which the recessedend inf-the control':bar-':extends, and which has'a longitudinaltgroove -thereinpa slidable and manually operable pushpiece carried by the body, a cam pivotally-mounted-on thepush-piec'e toserveasa-stop for limiting movement of the control bar in the directionfor increasing the pump output," the cam being provided with a lobewhich is slidable along the groove in the body, and also with afinger-like extension which in one position of the cam can enterthe'recess -in the end' of the control bar for enabling the portion ofthe cam at the root of the finger-like extension to serve asthe stop,and a spring actingon both the camand the-push piece and servingnormally to retain the cam in another position in which the outer end ofits finger-like extension is out of alignment with the recess in the endof the control bar and can serve as the stop, the cam beingmovable'fi'om the second mentioned position to the first mentionedposition by contact of the lobe on the cam with one end of the groove inthe body in response to actuation of the push piece, and beingreturnable by the spring to the second mentioned positionfollowingr'elease of the push piece and'retraction ofthe control barfrom the earn.

No references cited.

